CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Other Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury	Noncontrolling Interests	Opening retained earnings adjustments: adoption of new accounting standards	Opening retained earnings adjustments: adoption of new accounting standards Retained Earnings	Adjusted balance	Adjusted balance Common Stock	Adjusted balance Additional Paid-in Capital	Adjusted balance Other Capital	Adjusted balance Retained Earnings	Adjusted balance Accumulated Other Comprehensive Loss	Adjusted balance Treasury	Adjusted balance Noncontrolling Interests
Beginning balance, common stock (in shares) at Mar. 31, 2019		271,000										271,000
Beginning balance at Mar. 31, 2019	$ 8,287	$ 3	$ 6,435	$ (2)	$ 12,409	$ (1,849)	$ (8,902)	$ 193	$ 11	$ 11	$ 8,298	$ 3	$ 6,435	$ (2)	$ 12,420	$ (1,849)	$ (8,902)	$ 193
Beginning balance, treasury common stock (shares) at Mar. 31, 2019							(81,000)										(81,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee plans (in shares)		1,000
Issuance of shares under employee plans, net of forfeitures	93		113				$ (20)
Share-based compensation	115		115
Payments to noncontrolling interests	(154)							(154)
Other comprehensive income	146					146
Net income	1,078				900			178
Repurchase of common stock (in shares)							(14,000)
Repurchase of common stock	(1,934)						$ (1,934)
Change Healthcare share exchange (in shares)							(15,000)
Change Healthcare share exchange	(2,036)						$ (2,036)
Cash dividends declared	(294)				(294)
Other	(3)	$ (1)		2	(4)
Ending balance common stock (in shares) at Mar. 31, 2020		272,000										272,000
Ending balance at Mar. 31, 2020	5,309	$ 2	6,663	0	13,022	(1,703)	$ (12,892)	217	$ (13)	$ (13)	$ 5,296	$ 2	$ 6,663	$ 0	$ 13,009	$ (1,703)	$ (12,892)	$ 217
Ending balance, treasury common stock (shares) at Mar. 31, 2020							(110,000)										(110,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee plans (in shares)		1,000
Issuance of shares under employee plans, net of forfeitures	64		92				$ (28)
Share-based compensation	151		151
Payments to noncontrolling interests	(177)							(177)
Other comprehensive income	223					223
Net income	(4,383)				(4,539)			156
Exercise of put right by noncontrolling shareholders of McKesson Europe AG	3		3
Repurchase of common stock (in shares)							(5,000)
Repurchase of common stock	(750)						$ (750)
Cash dividends declared	(270)				(270)
Other	18		16		2
Ending balance common stock (in shares) at Mar. 31, 2021		273,000
Ending balance at Mar. 31, 2021	$ 175	$ 2	6,925	0	8,202	(1,480)	$ (13,670)	196
Ending balance, treasury common stock (shares) at Mar. 31, 2021	(115,000)						(115,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee plans (in shares)		2,000
Issuance of shares under employee plans, net of forfeitures	$ 149		220				$ (71)
Share-based compensation	154		154
Payments to noncontrolling interests	(155)							(155)
Other comprehensive income	112					116		(4)
Net income	1,279				1,114			165
Exercise of put right by noncontrolling shareholders of McKesson Europe AG	8		178			(170)
Repurchase of common stock (in shares)							(15,000)
Repurchase of common stock	(3,508)		(204)				$ (3,304)
Reclassification of McKesson Europe redeemable noncontrolling interests	287							287
Reclassification of recurring compensation to other accrued liabilities	(7)							(7)
Cash dividends declared	(279)				(279)
Other	(7)		2		(7)			(2)
Ending balance common stock (in shares) at Mar. 31, 2022		275,000
Ending balance at Mar. 31, 2022	$ (1,792)	$ 2	$ 7,275	$ 0	$ 9,030	$ (1,534)	$ (17,045)	$ 480
Ending balance, treasury common stock (shares) at Mar. 31, 2022	(130,000)						(130,000)